ETC EUP7981

芯美电子
EUP7981
150mA Low-Noise LDO in SC-70
DESCRIPTION
FEATURES
The EUP7981 is an efficient, CMOS voltage regulator
optimized for ultra-low-noise applications. It offers
high output accuracy, extremely low dropout voltage
low ground current and fast start-up time.
The EUP7981 provides a very low noise output, ideal
for RF applications where a clean voltage source is
required. A noise bypass pin is also available for
further reduction of output noise.
Designed specifically for handheld and batterypowered devices, the EUP7981 provides a
TTL-logic-compatible enable pin. When disabled,
power consumption drops nearly to zero.
The EUP7981 also works with low-ESR ceramic
capacitors, reducing the amount of board space
necessary for power applications, critical in handheld
wireless devices.
Available in the SC-70 package, the EUP7981 offers a
wide range of output voltages. Key features include
current limit, thermal shutdown and faster transient
response.
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Space-Saving 5-pin SC-70 Package
2.5V to 5.5V Input Voltage Range
50µV(rms) Output Noise
140mV Dropout @ 150mA
75dB PSRR at 1kHz
Low 70µA Ground Current
150mA Output Current
Stability with 1µF Ceramic Output Capacitors
Excellent Load/Line Transient
Thermal Shutdown and Current Limit
Protection
Available in 1.2V,1.5V,1.8V,1.85V,2.5V,2.8V,
2.85V, 3.0V ,3.3V and Adjustable Voltages
RoHS Compliant and 100% Lead (Pb)-Free
APPLICATIONS
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Cellular Phones
Bluetooth Portable Radios and Accessories
PDA and Palmtop Computers
Consumer/Personal Electronics
Block Diagram
Figure 1.
DS7981
Ver1.1
Apr. 2008
1
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芯美电子
EUP7981
Typical Application Circuit
Figure 2.
Pin Configurations
Package Type
Pin
Configurations
SC-70
Pin Description
PIN
PIN
VIN
1
Input voltage of the LDO
GND
2
Common ground
VEN
3
Enable input logic, enable high
BYPASS
ADJ
VOUT
DS7981
Ver1.1
4
5
Apr. 2008
DESCRIPTION
Optional bypass capacitor for noise reduction
Adjustable regulator feedback input. Connect to resistor divider.
Output voltage of the LDO
2
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EUP7981
Ordering Information
Order Number
Package Type
Marking
Operating Temperature Range
EUP7981-12NIR1
SC-70
MT □ □
-40 °C to 125°C
EUP7981-15NIR1
SC-70
MC □ □
-40 °C to 125°C
EUP7981-18NIR1
SC-70
MD □ □
-40 °C to 125°C
EUP7981-185NIR1
SC-70
MU □ □
-40 °C to 125°C
EUP7981-25NIR1
SC-70
MB □ □
-40 °C to 125°C
EUP7981-28NIR1
SC-70
ME □ □
-40 °C to 125°C
EUP7981-285NIR1
SC-70
MF □ □
-40 °C to 125°C
EUP7981-30NIR1
SC-70
MG □ □
-40 °C to 125°C
EUP7981-33NIR1
SC-70
MH □ □
-40 °C to 125°C
EUP7981NIR1
SC-70
MA □ □
-40 °C to 125°C
EUP7981- □□□ □ □ □ □
Lead Free Code
1: Lead Free 0: Lead
Packing
R: Tape & Reel
Operating temperature range
I: Industry Standard
Package Type
N: SC-70
Output Voltage
12: 1.2V
15: 1.5V
18: 1.8V
185:1.85V
25: 2.5V
28: 2.8V
285: 2.85V 30: 3.0V
33: 3.3V
Blank: Adjustable
Absolute Maximum Ratings
„
„
„
„
„
„
„
„
VIN,VEN ------------------------------------------------------------------------------- -0.3 to 6V
VOUT ----------------------------------------------------------------- -0.3 to (VIN+0.3) ≦ 6V
Junction Temperature --------------------------------------------------------------------- 150°C
Storage Temperature Range ---------------------------------------------------- -65°C to +150°C
Lead Temperature -------------------------------------------------------------------------- 260°C
Maximum Power Dissipation SC-70 ---------------------------------------------------0.3W
Thermal Resistance θJA(SC-70) --------------------------------------------------------- 320°C/W
ESD Rating
Human Body Model --------------------------------------------------------------------- 2kV
Operating Ratings
„
„
„
DS7981
Ver1.1
VIN -------------------------------------------------------------------------------------- 2.5 to 5.5V
VEN ------------------------------------------------------------------------- 0 to (VIN+0.3) ≦ 5.5V
Operating Temperature Range ------------------------------------------------- -40°C to +125°C
Apr. 2008
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芯美电子
EUP7981
Electrical Characteristics
Conditions: VIN=VOUT+0.5V or 2.5V whichever is greater,VEN=VIN,CIN=1uF,COUT=1uF,TA=-40~85℃
,Unless otherwise specified.
Symbol
Parameter
Conditions
Input Voltage
∆VOUT Output Voltage Accuracy
IOUTMAX Maximum Output Current
IOUT=1mA,TA=25℃
5.5
2
V
%
IOUT=1mA,TA=-40℃ to 85℃
-3
3
%
TA>0℃
150
150
Current Limit
VOUT=VOUT(nom) × 90%, TA>0℃
VDROP
Dropout Voltage (Note1)
Quiescent Current
VLNR
Line Regulation
VLDR
Load Regulation
ISHDN
Shutdown Supply Current
PSRR
Power Supply Ripple Rejection
Unit
2.5
-2
ILIMIT
IQ
EUP7981
Min
Typ
Max.
mA
220
400
mA
IOUT=150mA
140
240
mV
IOUT=1mA
VIN=(VOUT+0.5V) to 5.5V,
IOUT=1mA
1mA ≤ IOUT ≤ 150mA
70
160
µA
0.02
0.25
%/V
0.002
0.013
%/mA
1
µA
75
dB
Output Noise Voltage (Bypass)
VEN=0,TA=25℃
VIN=(VOUT+1V)DC+0.5VP-P
f=1kHz, ILOAD=10mA
f=10Hz~100kHz, ILOAD=10mA
50
µV
Output Noise Voltage (ADJ)
f=10Hz~100kHz, ILOAD=10mA
239
µV
Turn-on Time (Note2)
RLOAD=50Ω,TA=25℃
200
µs
VIN=2.5V to 5.5V
0.4
V
VFB
VENL (Maximum Low Level
Input Voltage at EN)
VENH (Minimum high Level
Input Voltage at EN)
VEN Input Bias Current
FB Input Bias Current (ADJ
Version)
FB Pin Voltage (ADJ Version)
TSD
Thermal Shutdown Temperature
155
℃
Thermal Shutdown Hysteresis
15
℃
VENL
VENH
∆TSD
VIN=2.5V to 5.5V
1.5
V
VIN=5.5V, VEN=0 or 5.5V
1
nA
VIN=5.5V, VFB=1.3V
1
nA
TA=25℃
1.176
1.2
1.224
Note 1: Dropout is defined as VIN-VOUT when VOUT is 100mV below the value of VOUT for VIN=VOUT+0.6V
Note 2: Test time needed for VOUT to reach 90% of final value.
DS7981
Ver1.1
Apr. 2008
4
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V
芯美电子
EUP7981
Typical Operating Characteristics
OUTPUT VOLTAGE ACCURACY vs. LOAD CURRENT
0.4
OUTPUT VOLTAGE vs. INPUT VOLTAGE
2.5
IOUT=0mA
2.0
DEVIATION (%)
OUTPUT VOLTAGE (V)
3.0
1.5
1.0
0.2
0.0
-0.2
IOUT=120mA
0.5
-0.4
0.0
0
1
2
3
4
INPUT VOLTAGE (V)
5
0
6
100
120
120
DROPOUT VOLTAGE (mV)
0.8
IOUT=1mA
0.4
0.0
-0.4
-0.8
-40
o
Temp=85 C
o
Temp=25 C
80
40
o
Temp=-40 C
0
-15
10
35
60
0
85
20
40
60
80
100
120
LOAD CURRENT (mA)
o
Temperature ( C)
GROUND CURRENT vs. INPUT VOLTAGE
GROUND CURRENT vs. LOAD CURRENT
200
200
IOUT=120mA
160
GROUND CURRENT (uA)
GROUND CURRENT (uA)
40
60
80
LOAD CURRENT (mA)
DROPOUT VOLTAGE vs. LOAD CURRENT
OUTPUT VOLTAGE ACCURACY vs. TEMPERATURE
DEVIATION (%)
20
120
80
IOUT=0mA
40
0
0
1
2
3
4
5
Ver1.1
Apr. 2008
Vin=5.5V
120
Vin=3.3V
80
40
0
6
0
INPUT VOLTAGE (V)
DS7981
160
20
40
60
80
LOAD CURRENT (mA)
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100
120
芯美电子
EUP7981
GROUND CURRENT vs. TEMPERATURE
GROUND CURRENT (uA)
120
100
80
60
40
20
0
-40
DS7981
-20
Ver1.1
0
20
40
60
80
o
TEMPERATURE ( C)
Apr. 2008
100 120 140
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芯美电子
DS7981
Ver1.1
Apr. 2008
EUP7981
7
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EUP7981
Application Note
capacitance can drop by more than 50% as the
temperature goes from 25°C to 85°C. Therefore, X7R
is recommended over Z5U and Y5V in applications
where the ambient temperature will change
significantly above or below 25°C.
External Capacitors
Like any low-dropout regulator, the EUP7981 requires
external capacitors for regulator stability. The
EUP7981 is specifically designed for portable
applications requiring minimum board space and
smallest components. These capacitors must be
correctly selected for good performance.
Noise Bypass Capacitor
Connecting a 0.01µF capacitor between the CBYPASS
pin and ground significantly reduces noise on the
regulator output. This cap is connected directly to a
high impedance node in the bandgap reference circuit.
Any significant loading on this node will cause a
change on the regulated output voltage. For this reason,
DC leakage current through this pin must be kept as
low as possible for best output voltage accuracy. The
types of capacitors best suited for the noise bypass
capacitor are ceramic and film.
Unlike many other LDO’s, addition of a noise
reduction capacitor does not effect the load transient
response of the device.
Input Capacitor
An input capacitance of 1µF is required between the
EUP7981 input pin and ground (the amount of the
capacitance may be increased without limit).
This capacitor must be located a distance of not more
than 1cm from the input pin and returned to a clean
analog ground. Any good quality ceramic, tantalum, or
film capacitor may be used at the input.
If a tantalum capacitor is used at the input, it must be
guaranteed by the manufacturer to have a surge current
rating sufficient for the application.
There are no requirements for the ESR on the input
capacitor, but tolerance and temperature coefficient
must be considered when selecting the capacitor to
ensure the capacitance will be 1µF over the entire
operating temperature range.
Adjustable Operation
The adjustable version of the EUP7981 has an output
voltage range of 1.2V to 4.5V. The output voltage of
the EUP7981 adjustable regulator is programmed
using an external resistor divider as shown in Figure3.
The output voltage is calculated using:
Output Capacitor
The EUP7981 is designed specifically to work with
very small ceramic output capacitors. A ceramic
capacitor (temperature characteristics X7R, X5R, Z5U,
or Y5V) in 1 to 22µF range with 5mΩ to 500mΩ ESR
range is suitable in the EUP7981 application circuit.
The output capacitor must meet the requirement for
minimum amount of capacitance and also have an
ESR (Equivalent Series Resistance) value which is
within a stable range (5mΩ to 500mΩ)
V =V
O
Apr. 2008
R
R
1)
2
Utilize the following equation for adjusting the output
to a particular voltage:

V
PI = R 2  O − 1
1.2V 
Choose R2=50k to optimize accuracy, power supply
rejection, noise and power consumption.
Capacitor Characteristics
The EUP7981 is designed to work with ceramic
capacitors on the output to take advantage of the
benefits they offer: for capacitance values in the range
of 1µF to 4.7µF range, ceramic capacitors are the
smallest, least expensive and have the lowest ESR
values (which makes them best for eliminating high
frequency noise). The ESR of a typical 1µF ceramic
capacitor is in the range of 20mΩ to 40mΩ, which
easily meets the ESR requirement for stability by the
EUP7981.
The ceramic capacitor’s capacitance can vary with
temperature. The capacitor type X7R, which operates
over a temperature range of -55°C to +125°C, will
only vary the capacitance to within ±15%. Most large
value ceramic capacitors ( ≈ 2.2µF) are manufactured
with Z5U or Y5V temperature characteristics. Their
Ver1.1
× (1 +
Where:
Vref= 1.2V typ. (the internal reference voltage)
No-Load Stability
The EUP7981 will remain stable and in regulation
with no external load. This is specially important in
CMOS RAM keep-alive applications.
DS7981
ref
Figure3. Adjustable Regulator with Resistors
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EUP7981
On/Off Input Operation
The EUP7981 is turned off by pulling the VEN pin low,
and turned on by pulling it high. If this feature is not
used, the VEN pin should be tied to VIN to keep the
regulator output on at all time. To assure proper
operation, the signal source used to drive the VEN
input must be able to swing above and below the
specified turn-on/off voltage thresholds listed in the
Electrical Characteristics section under VIL and VIH.
Fast Start up
The EUP7981 output starts up after Vref voltage
reaches its final value (1.2V nomial). The start-up time
is determined by the time constant of the bypass
capacitor. The smaller the capacitor value., the shorter
the start-up time, but less noise gets reduced. As a
result, start-up time and noise reduction need to be
taken into design consideration when choosing the
value of the bypass capacitor.
DS7981
Ver1.1
Apr. 2008
9
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芯美电子
EUP7981
Packaging Information
SC-70
SYMBOLS
A
A1
b
D
E
E1
e
L
DS7981
Ver1.1
Apr. 2008
MILLIMETERS
MIN.
MAX.
0.80
1.10
0.025
0.10
0.15
0.40
2.00
1.25
1.90
2.30
0.65
0.21
0.46
INCHES
MIN.
0.031
0.001
0.006
MAX.
0.044
0.004
0.016
0.079
0.049
0.075
0.091
0.026
0.008
0.018
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